1. Make sure your extruder heads are totally clean. Remove them and soak in acetone as discussed elsewhere on the net. This is why our prints randomly stop after a few layers- the tip is partially clogged (my theory).
1.5 Make sure the knurled filament wheels in the extruder assembly are completely clean of powered filament. Otherwise they can lose their grip on incoming filament. This is also a contributing factor for print stoppage.

Now for adhesion issues:

2. Try ABS juice (acetone with a tiny bit of ABS dissolved in it) to "clean" the build plate.
3. Level your buildplate WHEN IT IS HOT. Things change between cold and hot on ours.
4. We have had great success with the buildplate hotter than specified. We go from 130 to 140 C with really good luck.